Structures of Native and Regenerated Celluloses

纤维素 化学
作者
John Blackwell,Francis J. Kolpak,K. H. Gardner
出处
期刊:Acs Symposium Series 卷期号:: 42-55 被引量:21
标识
DOI:10.1021/bk-1977-0048.ch004
摘要

The crystal structures of native and regenerated celluloses have been determined using x-ray diffraction and least squares refinement techniques. Both structures have monoclinic unit cells containing sections of two chains with 21 screw axes. Models containing both parallel and antiparallel chains were refined in each case by comparison with the x-ray intensities for Valonia cellulose I and rayon cellulose II. For native cellulose, the results show a preference for a system of parallel chains (i.e. all the chains have the same sense). The refinement orients the -CH2OH groups close to the tg conformation such that an 0(6)···H-0(2') intramolecular hydrogen bond is formed. The structure also contains an 0(3)-H···0(3) intermolecular bond along the a axis. All these bonds lie in the 020 plane, and the native structure is an array of staggered hydrogen bonded sheets. In contrast, for regenerated cellulose the only acceptable structure contains antiparallel chains (i.e. the chains have alternating sense). The CH2OH groups of the corner chain are oriented close to the gt position; those of the center chain are close to the tg position. Both center and corner chains have the 0(3)-H···0(5') intramolecular bond and the center chain also has an 0(2')-H···0(6) intramolecular bond. Intermolecular hydrogen bonding occurs along the 020 planes: 0-(6)-H···0(2) bonds for the corner chains and 0(6)-H···0(3) bonds for the center chains, and also along the 110 planes, with a hydrogen bond between 0(2)-H of the corner chain and 0(2') of the center chain. The major consequence of these structures is that native cellulose is seen as extended chain polymer single crytals. The cellulose II structure is compatible with regular chain folding, although there is no direct evidence for such folding.
最长约 10秒,即可获得该文献文件

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
PDF的下载单位、IP信息已删除 (2025-6-4)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
2秒前
2秒前
inin发布了新的文献求助20
4秒前
科研通AI2S应助琪琪的采纳,获得10
4秒前
卓隶发布了新的文献求助10
4秒前
SciGPT应助董海涛采纳,获得10
5秒前
傻傻的小虾米完成签到,获得积分10
5秒前
5秒前
6秒前
科研通AI2S应助科研通管家采纳,获得10
6秒前
思源应助清新的访冬采纳,获得10
6秒前
ding应助科研通管家采纳,获得10
6秒前
6秒前
wulin应助科研通管家采纳,获得10
7秒前
华仔应助山猪吃细糠采纳,获得10
7秒前
zho应助科研通管家采纳,获得10
7秒前
研友_VZG7GZ应助科研通管家采纳,获得10
7秒前
烟花应助科研通管家采纳,获得10
7秒前
我是老大应助科研通管家采纳,获得10
7秒前
科研通AI5应助科研通管家采纳,获得30
7秒前
7秒前
科研通AI2S应助科研通管家采纳,获得10
7秒前
diudiu发布了新的文献求助10
7秒前
今后应助科研通管家采纳,获得10
7秒前
卷心小菜狗完成签到,获得积分10
7秒前
特安谭完成签到,获得积分10
9秒前
9秒前
叶听枫完成签到,获得积分10
10秒前
11秒前
卓隶完成签到,获得积分10
11秒前
Orange应助如此采纳,获得10
12秒前
安安完成签到,获得积分10
13秒前
Rinkki发布了新的文献求助10
13秒前
14秒前
15秒前
19秒前
scsc完成签到,获得积分20
19秒前
冷静的哈密瓜完成签到,获得积分10
20秒前
22秒前
研友_ngX12Z发布了新的文献求助10
22秒前
高分求助中
Picture Books with Same-sex Parented Families: Unintentional Censorship 1000
A new approach to the extrapolation of accelerated life test data 1000
ACSM’s Guidelines for Exercise Testing and Prescription, 12th edition 500
Microbiology and Health Benefits of Traditional Alcoholic Beverages 400
Indomethacinのヒトにおける経皮吸収 400
Phylogenetic study of the order Polydesmida (Myriapoda: Diplopoda) 370
基于可调谐半导体激光吸收光谱技术泄漏气体检测系统的研究 310
热门求助领域 (近24小时)
化学 材料科学 医学 生物 工程类 有机化学 生物化学 物理 内科学 纳米技术 计算机科学 化学工程 复合材料 遗传学 基因 物理化学 催化作用 冶金 细胞生物学 免疫学
热门帖子
关注 科研通微信公众号,转发送积分 3979984
求助须知:如何正确求助?哪些是违规求助? 3524121
关于积分的说明 11219921
捐赠科研通 3261562
什么是DOI,文献DOI怎么找? 1800703
邀请新用户注册赠送积分活动 879263
科研通“疑难数据库(出版商)”最低求助积分说明 807232